I was changing my oil today, and when I went to put in the new oil I noticed that there was a little milky substance under the oil filler cap. I have seen this on other vehicles that I have had before. I just was wondering if this is bad, or what causes this. Thanks!

2004 Titan SE

Mods- A heck of a lot more than I had before I found this forum The best beer in the world, is the open bottle in my hand If I'm not here, I'll be somewhere else.

Antifreeze in the oil causes milky oil, 99% of the time the milky oil under the oil cap is simply from condensation. This is more likely to appear when people only drive their vehicles short distances at a time where the engine doesn't have enough time to get up to temperature and boil off the moisture that has been pulled into the engine. This is especially so with oil filler caps that sit atop a filler neck instead of being directly on the valve cover.

I wouldn't be concerned, this is actually quite common with a lot of vehicles.

VWs are famous for this also. Yahooligan is right. It's just condensation more commonly found in vehicles that don't get up to full operating temperature long enough to burn it off.....also, it's more common to see in colder weather.

Antifreeze in the oil causes milky oil, 99% of the time the milky oil under the oil cap is simply from condensation. This is more likely to appear when people only drive their vehicles short distances at a time where the engine doesn't have enough time to get up to temperature and boil off the moisture that has been pulled into the engine. This is especially so with oil filler caps that sit atop a filler neck instead of being directly on the valve cover.

I wouldn't be concerned, this is actually quite common with a lot of vehicles.

My 99' Grand Cherokee used to have this problem as well, Jeep actualy designed a different oil filler cap and neck to prevent the foam. but as everyone said before me, don't worry about it.